CONSTRUCTION OF NON-PATHOGENIC PSEUDOMONAS SYRINGAE STRAINS TO CONTROL BACTERIAL BLAST AND CANKER OF STONE FRUITS

GENES CONFERRING BASIC PATHOGENICITY AND HOST RANGE IN A PSEUDOMONAS SYRINGAE PV. SYRINGAE (PSS) STRAIN THAT INFECTS CHERRY, PEACH, APRICOT, PEAR, ALMOND, AND SORGHUM WILL BE LOCALIZED. GENETIC LOCI THAT CONFER THE ABILITY OF PSS TO GROW EPIPHYTICALLY WILL BE IDENTIFIED. THESE GENES, ONCE BETTER DEFINED, WILL BE USED TO CONSTRUCT NON-PATHOGENIC FORMS OF PSS, THAT ORIGINALLY INFECTED PEACH AND ALMOND, TO BE EVALUATED IN DISEASE CONTROL TESTS FOR BLOSSOM BLAST AND EVENTUALLY CANKER CONTROL. THESE APPROACHES HAVE GENERAL APPLICABILITY TO THE CONSTRUCTION OF A WIDE RANGE OF BIOLOGICAL CONTROL OR BIOLOGICAL DELIVERY SYSTEMS BASED ON EPIPHYTIC P. SYRINGAE. THE ABILITY TO ELIMINATE PATHOGENICITY OR RESTRICT HOST RANGE IN A DIRECTED MUTAGENESIS SYSTEM WILL EVENTUALLY BE VALUABLE TO REDUCING CERTAIN CONCERNS OF ENVIRONMENTAL RISK IN THE USE OF ENGINEERED STRAINS. EQUALLY, ONCE DEMONSTRATED, THE DELETION OF WELL CHARACTERIZED REGIONS CONFERRING PATHOGENICITY OR EPIPHYTIC GROWTH WILL OBVIATE THE NEED TO CONDUCT LENGTHY AND COSTLY PATHOGENICITY AND HOST RANGE STUDIES CURRENTLY REQUIRED BY REGULATORY AGENCIES. STRAINS OF P. SYRINGAE, EVEN FROM NON-ENDEMIC SOURCES CAN BE USED INENVIRONMENTAL TESTS OF COMMERCIAL APPLICATIONS WITHOUT CONCERN FOR INTRODUCING EXOTIC PATHOGENS.